Question

The thickness of a timber frame may vary between _______

(a) 20-35 mm

(b) 60-75 mm

(c) 20-35 cm

(d) 60-75 cm

The question was posed to me in quiz.

The origin of the question is Door Frames topic in section Doors, Windows and Ventilators of Construction & Building Materials

Answer 1

Correct choice is (b) 60-75 mm

The best I can explain: Depending upon the size of the door opening and the type of timber used, the thickness of a timber frame may vary between 60-75 mm. The same thickness is used for the horizontal and vertical members of the door frame.